<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h2>这是首页，点击下面的展示所有书籍即可跳转到全部书籍的列表页</h2>
<b>{{ pr_str }}</b>
<br><hr>
<a href="/book_list">显示所有书籍</a>
</body>
</html>